Orange-red acridin dye.



Ihfo. V9450 52..

nrrrnid h'ra'rias Patented July" t, 1905.

a'rnnir OTTO EBOHST, OF HOOHSTON-Tlll ll l-MAIN, GERh IANY, ASSlG-NOH TOFARE- WERKE, VORM. MEISTER, LUOIUS 8: BRUNlNG, OF llOOHf B"-ON-THE-MAIN, GERl IANY, A CORPORATION OF GERMANY.

OFfANGIfE Il flEW ftwfdllll'lim DYE.

fiPEGIFICATION forming part of Letters Patent No. 794,052, dated July4t, 1905.

Application filed August 81, 1904. Serial No. 222,836.

To all 7071/01, (It may concern.-

Be it known that l, Orr'ro Sousa, Ph. 1)., chemist, a citizen of theEmpire of Germany, residing at ffochst-on-the-Main, Germany, haveinvented certain new and useful improvements in the lvfanufacture ofOrange-Red Dyestuffs of the Acridin Series, of which the following is aspecification.

l have found that the orange-yellow acridini um dyestuffs or their leucocompounds derived from acridin-yellow and obtained, for instance, by theaction of hydrochloric acid and alcohol on leuco acridin-yellow may betransformed into orange-red dyestuffs if heated in an open vessel withformaldehyde in OODCGl'lbl'flf-Gd sulfuric acid.

Nothing has hitherto been known about the action of formaldehyde andconcentrated sulfuric acid on acridinium compounds. lfn German PatentNo. 135,771 new acridin dyestuffs have been described, which may beobtained by heating under pressure acridinyellow or alkylated acridindyestuffs with formaldehyde and diluted mineral acids. An essentialdifference exists, however, between this process and that referred to.According to this process the dyestuffs are heated with concentratedsulfuric acid in an open vessel, while according to the German PatentNo. 135,771 the operation occurs with dilute mineral acid (hydrochloricacid) in a closed vessel under pressure. It is further stated in saidpatent that for one molecular proportion of dyestuif one molecularproportion of for inaldehyde to be used, and if more formaldehyde beused insoluble by-products are formed. Now according to this process atleast two or three molecular proportions of formaldehyde may beemployed, yet no formation of insoluble by-products occurs. By thedifferent procedure a new result is obtained, inasmuch as dyestuffs ofmuch redder shade can be produced than by the process of said patent.

Example: Fifty kilos of the dyestuff (salt or base) or its leucocompound, obtained by alkylating acridin-yellow with hydrochloric acidand alcohol, are dissolved in about five hundred kilos of sulfuric acidof 66 specific gravity, to which are added at about centigrade thirty tofifty kilos of formaldehyde, the whole being heated :for about one hourto 150 centigrade to 170 centigrmlewhile stirring. \Vhen cold, thesolution is poured into fifteen hundred liters of water, and smallquantities of a brownish dyeing dyestulf are salted outwith about twohundred kilos of common salt. The whole is then filtered, and from thefiltrate the dyestuff is completely 'n'ecipitated by adding about onehundred kilos of zinc chlorid and sufficient alkali until the greaterpart of the sulfuric acid is neutralized.

iVhen dry, the d yestu fl is a brown-red powder easily soluble in waterwith an orangeyellow color, dyeing cotton treated with tannin andleather orange-red shades. With concentrated sulfuric acid a yellowsolution of a decided green fluorescence is obtaiued,which on addinglittle water turns orange and on adding much Water becomes red. .[11alcohol the dyestuff is diflicultly soluble with an orange-red colorinsoluble in ether, benzene, and ligroin.

The dyestuff is not uniform, but consists for the greater part of anacridinium and for the rest of an acridin dyestuff, which owing to theirdifferent behavior toward ammonia may be easily separated. Whether thisacridinium dyestuff is identical with the highly alkylated one describedin said patentand obtained by means of concentrated sulfuric acid andmenthyl-alcohol could hitherto not be proved with certainty.

Having now described my invention, what I claim isl. The hereindescribed process for the manufacture of orange-red dyestuffs, whichconsists in heating to a high temperature with concentrated sulfuricacid and formaldehyde the products obtained by alkylating leuco acridin-yellow with hydrochloric acid and alcohol, substantially as setforth.

2. As new products, the orange-red dye stuffs obtained by heating to ahigh temperature with concentrated sulfuric acid and formaldehyde theproducts obtained by alkylatdifiicultly soluble with an orange-yellowcolor, IO insoluble in ether, benzene and ligroin.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

I OTTO SOHST Witnesses:

ALFRED BRISBOIs, BERNHARD LYDEOKER.

